1. Field of the Invention
The present invention relates to electrically operated locks for security doors, and more particularly to an automatically self locking electronic lock system for use with a safe or any other type security door.
2. Related Art
U.S. Pat. Nos. 4,926,664 and 5,033,282 show self locking electronic locks for use with safe doors wherein the associated locking mechanisms are automatically self locking. In the locking mechanisms of these prior patents, a lock bolt is normally biased into a locking position, and electronically driven means are provided for effecting unlocking by withdrawing the lock bolt against its bias from a locking engagement with bolt works. The prior patents show a lost motion connection being provided between the lock bolt and the electrically driven means whereby after opening of the safe door, the electrically driven means can be reversed, through the lost motion connection with the lock bolt, to release the lock bolt which is then free to return to its normally biased locking position.
In addition, the prior patents include blocking means separate from the connecting means between the lock bolt and the electrically driven means. The blocking means prevents unauthorized withdrawal of the lock bolt from its normally biased position, and consists of a leaf spring having a stop surface to contact and block withdrawal of the bolt. An engagement surface integral to the leaf spring engages the lost motion connection and deflects the leaf spring away from a position blocking the lock bolt upon operation of the lost motion connection in order to enable retraction of the lock bolt. Providing the blocking means as separate means from the connecting means increases the complexity of the prior art locks.
Electronic code input means are also well known in the art of electronic locks as in part disclosed in prior patents, U.S. Pat. Nos. 4,745,784, and 4,148,092, the disclosures of which are incorporated herein by this reference.